PULMONARY FUNCTION TEST-DLCO

SUMMARY

1. Carbon monoxide diffusing capacity (DLCO) is decreased by anything that interrupts gas-blood O₂ exchange (imapired O₂ exchange).
2. It implies a loss of affective alveolar-capillary interface.
3. Decreased DLCO: emphysema, ILD, pulmonary vascular diseases, anaemia.

4. Normal DLCO: asthma and chronic bronchitis, where there is no alveolar disease.

5. Increased DLCO: heart failure, diffuse alveolar hemorrhage, pulmonary infarction, and idiopathic pulmonary hemosiderosis (IPH), where there is increased blood flow to functional lungs.

6. Monitor in ILD to assess progress. Helps distinguish b/w emphysematous COPD (low DLCO) from chronic bronchitis & asthma (normal DLCO).

Reference(s)

Wilkinson, I., Furmedge, D. and Sinharay, R. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press. Get it on Amazon.
Feather, A., Randall, D. and Waterhouse, M. (2020). Kumar And Clark’s Clinical Medicine. 10th ed. S.L.: Elsevier Health Sciences. Get it on Amazon.
Hannaman, R. A., Bullock, L., Hatchell, C. A., & Yoffe, M. (2016). Internal medicine review core curriculum, 2017-2018. CO Springs, CO: MedStudy.
Therapeutic Guidelines. Melbourne: Therapeutic Guidelines Limited. https://www.tg.org.au [Accessed 2021].